report on the 11 th inter-laboratory comparison organised...

Report EUR 25999 EN

20 13

Four marker PAHs in spiked olive oil

Report on the 11th inter-laboratory comparison

organised by the European Union Reference

Laboratory for Polycyclic Aromatic Hydrocarbons

Stefanka Bratinova, Philippe Verlinde and

Thomas Wenzl

European Commission

Joint Research Centre

Institute for Reference Materials and Measurements

Contact information

Thomas Wenzl

Address: Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel, Belgium

E-mail: [email protected]

Tel.: +32 14 571 320

Fax: +32 14 571 783

http://irmm.jrc.ec.europa.eu/

http://www.jrc.ec.europa.eu/

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JRC 81648

EUR 25999 EN

ISBN 978-92-79-30497-2 (pdf)

ISSN 1831-9424 (online)

doi: 10.2787/61833

Luxembourg: Publications Office of the European Union, 2013

© European Union, 2013

Reproduction is authorised provided the source is acknowledged.

Printed in Belgium

3

Report on the 11th inter-laboratory comparison organised by the European Union Reference Laboratory for Polycyclic Aromatic

Hydrocarbons

Four marker PAHs in spiked olive oil

Stefanka Bratinova, Philippe Verlinde and Thomas Wenzl

EC-JRC-IRMM (2013)

4

Table of Contents

1. Executive summary .................................................................................................................... 5

2. Introduction ................................................................................................................................ 6

3. Scope ............................................................................................................................................ 7

4. Participating Laboratories ........................................................................................................ 8

5. Time frame .................................................................................................................................. 9

6. Confidentiality ............................................................................................................................ 9

7. Test materials .............................................................................................................................. 9

7.1 Preparation 9

7.2 Homogeneity and stability 10

7.3 Assigned value and standard deviation for proficiency assessment 10

8. Design of the proficiency test ................................................................................................... 11

9. Evaluation of Laboratories ...................................................................................................... 11

9.1 General 11

9.2 Evaluation criteria 12

9.3 Evaluation of results 12

9.4 Additional information extracted from the questionnaire 17

10. Follow-up actions for underperforming laboratories ........................................................... 18

11. Conclusions ............................................................................................................................... 18

12. Acknowledgements ................................................................................................................... 19

13. References ................................................................................................................................. 19

14. ANNEXES ................................................................................................................................. 20

5

1. Executive summary

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds consisting of fused aromatic rings; some of them are carcinogenic and mutagenic. Humans are exposed to PAHs via air and drinking water, but mostly by intake of food. To protect the wellbeing of consumers EU legislation introduced maximum levels for certain PAHs in food.

European Union food safety legislation created EU and national reference laboratories, which should contribute to a high quality and uniformity of analytical results. This objective can be achieved by activities such as the application of validated analytical methods, ensuring that reference materials are available, the organisation of comparative testing and the training of staff from laboratories.

This report presents the results of the eleventh inter-laboratory comparison (ILC) organised by the European Union Reference Laboratory for Polycyclic Aromatic Hydrocarbons (EU-RL PAHs) on the determination of the four EU marker PAHs, benz[a]anthracene (BAA), benzo[a]pyrene (BAP), benzo[b]fluoranthene (BBF) and chrysene (CHR), in olive oil spiked with 15+1 EU priority PAHs. It was conducted in accordance with ISO Standard 17043 and the IUPAC International Harmonized Protocol for the Proficiency Testing of Analytical Chemistry Laboratories.

In agreement with National Reference Laboratories (NRLs), the test material used in this exercise was commercial olive oil spiked with 15 + 1 EU priority PAHs. The spiked oil was prepared gravimetrically and values obtained from preparation were used to benchmark the results reported by participants.

Both officially nominated NRLs and official food control laboratories of the EU Member States were admitted as participants.

The participants were free to choose the method of analysis. The four EU marker PAHs were chosen as target analytes as limits for their sum were recently introduced in European legislation. The performance of the participating laboratories in the determination of the target PAHs in olive oil was expressed by both z-scores and zeta-scores. Those scores provide a normalised performance evaluation to make proficiency test (PT) results comparable. Laboratories complying with the PT scheme’s fitness for purpose criterion will commonly produce scores falling between - 2 and 2. The gravimetrical preparation concentrations, corrected for the purity of the reference materials were applied as assigned values for the proficiency assessment. The uncertainties of the assigned values were calculated taking into account the purity of the reference materials used and the weighing operation carried-out.

Participants also received a solution of PAHs in the solvent of their choice (either toluene or acetonitrile) with known PAH content for the verification of their instrument calibration.

This proficiency testing round has demonstrated the high competence of all participating laboratories in the analysis of regulated PAHs in an oily matrix. More than 90 % of the reported test results were graded with z-scores that were less than an absolute value of 2, indicating good agreement with the assigned reference values of the test material.

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2. Introduction

The Institute for Reference Materials and Measurements (IRMM) of the European Commission's Directorate General Joint Research Centre hosts the European Union Reference Laboratory for Polycyclic Aromatic Hydrocarbons in Food (EU-RL-PAH). One of its core tasks is to organise inter-laboratory comparisons (ILCs) for the National Reference Laboratories (NRLs) [i, ii].

Polycyclic aromatic hydrocarbons (PAHs) constitute a large class of organic substances. The chemical structure of PAHs consists of two or more fused aromatic rings. PAHs may be formed during the incomplete combustion of organic compounds and can be found in the environment. In food, PAHs may be formed during industrial food processing and domestic food preparation, such as smoking, drying, roasting, baking, frying, or grilling.

In 2002 the European Commission Scientific Committee on Food identified 15 individual PAHs as being of major concern for human health. These 15 EU priority PAHs should be monitored in food to enable long-term exposure assessments and to verify the validity of the use of the concentrations of benzo[a]pyrene (BAP) as a marker for a “total-PAH content” [iii]. The toxicological importance of these compounds was confirmed in October 2005 by the International Agency for Research on Cancer (IARC), which classified BAP as carcinogen to human beings (IARC group 1), cyclopenta[cd]pyrene - CPP, dibenzo[a,h]anthracene - DHA, and dibenzo[a,l]pyrene - DLP as probably carcinogenic to human beings (group 2a), and nine other EU priority PAHs as possibly carcinogenic to human beings (group 2b) [iv].

As a consequence, the European Commission (EC) issued Commission Regulation (EC) No 1881/2006 setting maximum levels of benzo[a]pyrene in food, Commission Regulation (EC) No 333/2007 laying down sampling methods and performance criteria for methods of analysis for the official control of benzo[a]pyrene levels in foodstuffs, and Commission Recommendation 2005/108/EC on the further investigation into the levels of PAHs in certain foods [v, vi, vii].

To evaluate the suitability of BaP as a marker for occurrence and toxicity of PAHs in food, the European Commission asked the European Food Safety Authority (EFSA) for a review of the previous risk assessment on PAHs carried by the Scientific Committee on Food (SCF).

The scientific opinion on polycyclic aromatic hydrocarbons in food was published by EFSA in June 2008 [viii]. EFSA concluded that benzo[a]pyrene was not a suitable indicator for the occurrence of PAHs in food and that four (PAH4) or eight PAHs (PAH8) were more suitable indicators for the occurrence of PAHs in food. However, PAH8 does not provide much added value compared to PAH4. Following these conclusions the Standing Committee on the Food Chain and Animal Health agreed to base risk management measures on four PAHs (PAH4) - BAA, BAP, BBF, and CHR. However, maximum levels for BAP would be maintained to ensure comparability with historical data. In the following the PAH4 will be also indicated as "the four EU marker PAHs". They are listed in 7HTable 1. A maximum level for the sum of the four PAHs was included in the amendment of Commission Regulation (EC) No 1881/2006 [vi]. Coherently, also Commission Regulation (EC) No 333/2007 [vii] which lays down minimum method performance criteria was revised by Commission Regulation (EC) No 836/2011.

Table 1: Names and structures of the four EU marker PAHs.

1 Benz[a]anthracene (BAA)

2 Benzo[a]pyrene (BAP)

3 Benzo[b]fluoranthene (BBF)

4 Chrysene

(CHR)

7

3. Scope

As specified in Regulation (EC) No 882/2004 on official controls performed to ensure the verification of compliance with food and feed law, animal health and animal welfare rules [ii]2, one of the core duties of EU-RLs is organising inter-laboratory comparison tests (ILCs).

This inter-laboratory comparison study aimed to evaluate the measurement capabilities of the National Reference Laboratories (NRLs) and EU official food control laboratories (OCLs) for the four EU marker PAHs in olive oil. The appropriateness of the reported measurement uncertainty was also tested as this parameter is important in the compliance assessment of food with EU maximum levels.

The ILC was designed and evaluated according to ISO Standard 17043:2010. [ix ].

8

4. Participating Laboratories

Officially nominated NRLs and OCLs of the EU Member States were admitted as participants. The participants are listed in Table 2 and Table 3 respectively. Table 2: List of participating National Reference Laboratories

Institute Country

AGES - Österreichische Agentur für Gesundheit und Ernährungssicherheit, Kompetenzzentrum Cluster Chemie

AUSTRIA

Scientific Institute of Public Health BELGIUM

SGL - State General Laboratory, Environmental and other Food Contamination Laboratory

CYPRUS

Nàrodní referenční laboratoř pro polycyklické aromatické uhlovodíky - Státní veterinární ústav Praha

CZECH REPUBLIC

Division of Food Chemistry, National Food Institute, Technical University of Denmark DENMARK

Food and Vet. Administration in Aarhus DENMARK

Tartu Laboratory of Health Protection Inspectorate ESTONIA

EVIRA - Finnish Food Safety Authority FINLAND

LABERCA - Laboratoire d'Etude des Résidus et des Contaminants dans les Aliments FRANCE

BVL - Bundesamt für Verbraucherschutz und Lebensmittelsicherheit GERMANY

GCSL - General Chemical State Laboratory - Food Division - Laboratory GREECE

Food Chain Safety Office, Food & Feed Safety Directorate, Food Toxicological NRL. HUNGARY

The Public Analyst's Laboratory Dublin IRELAND

Istituto Superiore di Sanità ITALY

BIOR - Institute of Food Safety, Animal Health and Environment LATVIA

National Veterinary Laboratory (National Food and Veterinary Risk Assessment Institute) LITHUANIA

Laboratoire National de Santé, Contrôle Alimentaire LUXEMBOURGE

RIKILT- Institute of Food Safety THE NETHERLANDS

NIFES - National Institute of Nutrition and Seafood Research NORWAY

National Institute of Public Health - National Institute of Hygiene POLAND

SVUPUDK - State Veterinary and Food Institute Dolný Kubín SLOVAKIA

Zavod za zdravstveno varstvo Maribor SLOVENIA

AESAN - Centro Nacional de Alimentaciòn (Spanish Food Safety and Nutrition Agency) SPAIN

National Food Agency SWEDEN

FERA - The Food and Environment Research Agency UNITED KINGDOM

All the registered 25 NRL's sent the results.

9

Table 3: List of participating Official Food Contro l Laboratories

Institute Country ANALYTEC AUSTRIA

Institut Dr. Wagner AUSTRIA

Umweltinstitut des Landes Vorarlberg AUSTRIA

State Veterinary Institute Olomouc CZECH REPUBLIC

STATE VETERINARY INSTITUTE JIIHLAVA CZECH REPUBLIC

Health Board - Tallin ESTONIA

LDA 22 FRANCE

Laboratoire Departemental de la Sarthe FRANCE

CVUA-MEL GERMANY

Chemisches Untersuchungsamt der Stadt Hagen GERMANY

Arpa Puglia ITALY

ASL Milano ITALY

NVWA THE NETHERLANDS

State Veterinary and Food Institution Kosice SLOVAKIA

State Veterinary and Food Institution Bratislava SLOVAKIA

LABORATORIO DE SALUD PÚBLICA DE MADRID SPAIN

CENTRO DE SALUD PÚBLICA DE ALICANTE SPAIN

All the 17 registered OCLs reported results.

5. Time frame

The ILC was agreed with the NRLs at the EU-RL PAH workshop in Geel on the 25th of April 2012. It was announced on the IRMM web page (see ANNEX 1) and invitation letters were sent to the laboratories on the 28th of September 2012 (see ANNEX 2). Test samples were dispatched (see ANNEX 3) on the 7th of November 2012 and the deadline for reporting of results was set to the 4th of January 2013.

The documents sent to the participants are presented in ANNEX 4.

6. Confidentiality

The identities of participants are kept confidential unless the participant provides a letter of consent to the PT organiser giving permission to disclose his/her details and results to a third party.

7. Test materials

7.1 Preparation The test materials of this PT round was olive oil spiked with 15+1 EU priority PAHs, in the following denoted as OIL. This matrix represents the food category 6.1.1 "Oils and fats, intended for direct human consumption or use as an ingredient in food" specified in Commission Regulation (EC)

10

No 835/2011, with a maximum level for BAP and for the sum of the four PAHs (in the following indicated as SUM) of 2.0 µg/kg and 10.0 µg/kg respectively.

Participants also received a solution of the four EU Priority PAHs in either acetonitrile or toluene (according to their choice, see ANNEX 3) with disclosed concentrations, which allowed them to check their instrument calibration against an independent reference. The technical specifications are provided in Annex 5.

The test material was prepared at the EU-RL PAH laboratories from four liters of olive oil, checked for absence of PAHs prior to the test material preparation. It was spiked with a PAH standard solution containing besides the four EU marker PAHs also other the other PAHs mentioned by the European Commission Scientific Committee on Food. The standard solution was prepared from neat certified reference materials (purchased from BCR®, Institute for Reference Materials and Measurements, Geel, Belgium, except CPP - purchased from Biochemisches Institut für Umweltkarzinogene, Großhansdorf, Germany, BCL - purchased from Dr. Ehrenstorfer, Germany, and DIP - purchased from Campro Scientific, Germany). Single standard stock solutions of each analyte were produced by substitution weighing of neat substance on a microbalance and dissolution in toluene. These standard stock solutions were mixed and diluted further gravimetrically with toluene to obtain the solution used for spiking the olive oil. After spiking, the test sample was homogenised over night by intensive stirring. Portions of about 20 g spiked olive oil test material were sealed under inert atmosphere in 25 ml amber glass ampoules.

7.2 Homogeneity and stability Homogeneity of the olive oil test sample was evaluated according to ISO Standard 13528. Ten ampoules of the olive oil test material were selected randomly and analysed by online-donor acceptor complex chromatography high performance liquid chromatography with fluorescence detection. The test material was rated sufficiently homogeneous (see ANNEX 6).

The stability of the test materials was evaluated by analysing the test material after the deadline for reporting of results. Significant differences of the analyte contents between the analysis results and the preparation concentrations were not found. Hence stability of the samples over the whole study period was assumed.

7.3 Assigned value and standard deviation for proficiency assessment The gravimetrical preparation concentrations, corrected for the purity of the reference materials were applied as assigned values for the proficiency assessment. The assigned values of the target PAHs are listed in Table 4.

The uncertainties of the assigned values were calculated taking into account the purity of the reference materials used and the weighing operation carried-out according to GUM [x].

The standard deviation for proficiency assessment, σP, was set for the individual analyte equal to the maximum tolerable uncertainty (Uf), which is calculated according to Equation 1 [xii]. A LOD value of 0.30 µg/kg, and α equal to 0.2 were applied for this purpose. The standard deviation for proficiency testing was calculated for the SUM parameter from the σP - values of the individual analytes applying the law of uncertainty propagation.

Equation 1 Uf = 22 )C((LOD/2) α+

where Uf relates to the maximum tolerated standard measurement uncertainty, LOD to the limit of detection, α to a numeric factor depending on the concentration C as given in Commission Regulation (EC) No 836/2011.

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Table 4: Analyte contents of the olive oil test material

Assigned value* U σP

Analyte Analyte short name µg/kg µg/kg µg/kg %

Benz[a]anthracene BAA 2.79 0.02 0.58 20.7

Benzo[a]pyrene BAP 2.27 0.03 0.48 21.1

Benzo[b]fluoranthene BBF 5.32 0.05 1.07 20.2

Chrysene CHR 2.77 0.03 0.57 20.7

Sum of the four marker PAHs SUM 13.15 0.07 1.43 10.9 * gravimetrical preparation concentration of the material for the individual analytes, respectively sum of the

individual concentrations for the SUM parameter σp standard deviation for proficiency assessment. U expanded uncertainty of the assigned value (k=2). For the individual analytes the standard uncertainty is equal to the square root of the sum of the squares of the uncertainties associated with each single operation involved in the preparation of the test material; for the SUM is equal to the combined standard uncertainty of the four analytes.

8. Design of the proficiency test

The design of the PT foresaw triplicate analyses of the test sample and reporting of the individual results of replicate analyses for the single analytes, in the following denoted as OIL_REP. Additionally a "value for proficiency assessment", in the following denoted as "final value - OIL_FIN", was requested for both the single analytes and the sum of the four PAHs. Both OIL_REP results and OIL_FIN results had to be reported corrected for recovery (and recovery had to be stated in the questionnaire together with other parameters of the method applied); OIL_FIN results had also to be accompanied by the respective expanded measurement uncertainty (with a coverage factor of 2). The OIL_FIN results were the values used for performance assessment.

Participants were asked to report besides analysis results also details of the applied analysis method (see ANNEX 7).

Each participant received at least one ampoule of a solution of the target PAHs in the chosen solvent (2 ml), with disclosed content, and at least one ampoule of OIL (20 ml).

9. Evaluation of Laboratories

9.1 General The results reported by participants are listed in ANNEX 8. In case the coverage factor k was not reported by the participant, a coverage factor of two was assumed (see the Outline in ANNEX 4). The most important evaluation parameter was the performance of the laboratories in the determination of the target PAHs in the olive oil test material, which was expressed by z-scores but zeta-scores were calculated as well considering the uncertainty of the test results as estimated by each participant.

12

9.2 Evaluation criteria z-Scores z-Scores were calculated based on the OIL_FIN values. Equation 2 presents the formula for calculation of z-scores.

Equation 2 ( )

P

assignedlab Xxz

σ−

=

where z refers to the z-score, xlab to the reported “value for proficiency assessment”, Xassigned to the assigned value, and σP to the standard deviation for proficiency testing. zeta-Scores In addition to z-scores, zeta-scores were calculated. In contrast to z-scores, zeta-scores describe the agreement of the reported result with the assigned value within the respective uncertainties. zeta-Scores were calculated according to Equation 3.

Equation 3 22assignedlab

assignedlab

uu

Xxzeta

+

−=

where zeta refers to the zeta-score, xlab to the reported “final value”, Xassigned to the assigned value, ulab to the standard measurement uncertainty of the reported result, and uassigned to the standard uncertainty of the assigned value. Whenever uncertainty was not reported by the laboratory, the corresponding zeta-score was not calculated.

Unsatisfactorily large zeta-scores might be caused by underestimated measurement uncertainties, large bias, or a combination of both. On the contrary, satisfactory zeta scores might be obtained even with high bias if the uncertainty is sufficiently high. However, legislation specifies maximum tolerable standard uncertainties. Uncertainties exceeding them are not considered fit-for-purpose. Therefore, the uncertainties reported by the participants for the four PAHs were checked whether they comply with the thresholds provided by the "fitness-for-purpose" function. The results reported by the participants and the maximum tolerated LOD of 0.3 µg/kg were applied for the calculation of respective threshold values. For the SUM parameter the agreement between reported standard measurement uncertainties and the combined standard uncertainty of the four EU marker PAHs was evaluated. The latter was derived via the law of error propagation from the uncertainties reported for the individual analytes. Non-compliant reported uncertainties are highlighted in Table 5 and Table 6.

The performance of the laboratories was classified according to ISO/IEC 17043:2010 [ix]. Following scheme is applied for the interpretation of zeta scores and z-scores:

|score| ≤ 2.0 = satisfactory performance 2.0<|score| < 3.0 = questionable performance |score| ≥ 3.0 = unsatisfactory performance

9.3 Evaluation of results The participants were requested to report for the four analytes the results of replicate measurements and a "value for proficiency assessment" (OIL_FIN), which is the result they wish to be applied for the calculation of performance indicators. z-Scores and zeta-scores were attributed only to these results. The individual results of replicate analyses were not rated.

13

Each laboratory had to report a total of 17 results (12 results for replicate measurements plus 5 values for proficiency assessment), therefore the reported number of results of registered participants was 714. The 42 participants in the study reported in total 698 results. One participant reported only value for proficiency assessment without replicates and another participant reported only two replicates and value for proficiency assessment.

About 94.4 % and about 90.5 % of the results reported from NRLs and OCLs respectively obtained a satisfactory z-score.

In Figures 1 and 2 overviews of the z-scores assigned to the results are given for NRLs and OCLs respectively. The larger the triangles, the larger were the differences to the assigned values. Red triangles indicate z-scores above an absolute value of three, whereas yellow triangles represent z-scores in the questionable performance range. For questionable and unsatisfactory scores, the corresponding score values are presented next to the triangles. The three non-satisfactory results of NRLs were reported by two participants; whereas in the case of OCLs the three non-satisfactory results were reported by one laboratory. The questionable results are in total 10.

The numerical values of the calculated z-scores are compiled in Table 5 for NRLs and OCLs respectively. z-Scores with an absolute value of above 2 are highlighted in red.

Table 6 presents the respective zeta-scores. As for the z-scores, data outside the satisfactory performance range are highlighted in red. The assessment of the performance of the participants based on the reported measurement uncertainty gave a less favourable picture. Only 78.4% and 77.6% respectively (for NRLs and OCLs) of the zeta-scores calculated for the four individual analytes and the SUM are within the range given by |zeta| ≤ 2. It has to be noted that the absolute value of the zeta-scores were for many participants much higher than the z-scores attributed to the same results. Consequently the laboratories perform according to internationally agreed standards, which form the basis for the z-scores, but seem to have partially difficulties in calculating realistic measurement uncertainty values. The establishment of proper measurement uncertainty values caused problems especially for the SUM parameter. The majority of participants reported for this parameter measurement uncertainty values different from the value which is derived by the law of uncertainty propagation.

Hence the EU-RL PAHs will continue to pay special attention to this parameter, in the ILCs to come, as it has major implications on the assessment of compliance of food with European legislation.

The graphical representations of the distribution of results for the individual analytes are given in ANNEX 8 together with the results of replicate analyses and Kernel density plots. Data are presented as reported by the participants.

For each analyte the figure shows the individual analysis results of the three replicate determinations. The assigned value is shown as green dotted line. The blue boxes represent the expanded uncertainties reported by participants for the "value for proficiency assessment". The arithmetic mean of the results of the individual participant is indicated in the blue boxes by a blue line. The red dotted lines represent deviations from the assigned value of ± 2σp.

As could be seen from the Kernel density plots the distribution of results for each analyte and for the sum of the analytes were close to a Gaussian distribution. The robust mean and the mode are very close to the assigned (reference) value, which demonstrates that the analysis was not biased.

The figures in ANNEX 9 are an aid to allow laboratories to compare the performance of their method to those of other participants with respect to bias (closeness to the assigned value, plotted on the x-axis) and precision (the standard deviation for repeatability, plotted on the y-axis). A vertical solid green line depicts the assigned value; laboratories are represented by blue dots (mean value of the replicates and the associated standard deviation of the replicates). The light blue area indicates the satisfactory performance area, which is defined by the assigned value ±2σP along the x-axis and by the

14

Figure 1: Graphical presentation of z-scores corresponding to the "values for proficiency assessment" reported by the NRLs for the contents of BAA, BAP, BBF, CHR, and the SUM parameter in the spiked olive oil test material.

Blue triangles indicate satisfactory performance; yellow triangles indicate questionable performance; red triangles indicate non-satisfactory performance; z-score values are presented above the triangles for the last two performance categories.

Z Score-3 0 3 -3 0 3 -3 0 3 -3 0 3 -3 0 3

MeasurandBAA BAP BBF CHR SUM

Labora

tory

101102103104105106107108109110111112113114115116117118119120121122123124515

2.523.04 3.23

-2.36 -2.79

-2.20

-3.03

Figure 2: Graphical presentation of z-scores corresponding to the "values for proficiency assessment" reported by the OCLs for the contents of BAA, BAP, BBF, CHR, and the SUM in the spiked olive oil test material. Blue triangles indicate satisfactory performance; yellow triangles indicate questionable performance; red triangles indicate non-satisfactory performance; z-score values are presented above the triangles for the latter performance category.

Z Score-3 0 3 -3 0 3 -3 0 3 -3 0 3 -3 0 3

MeasurandBAA BAP BBF CHR SUM

Labora

tory

501

502

503

504

505

506

507

508

509

510

511

512

513

514

516

517

518

2.45

2.93

2.51 2.87

4.81 8.89 8.22

-2.26 -2.76

15

Table 5: Compilation of z-scores calculated from the “results for proficiency assessment" reported by the NRLs and OCLs for test material OIL: z-scores outside the satisfactory range (|z| > 2) are highlighted in red.

SUM

Assigned value, µg/kg

σσσσρ, µg/kgResult z-score Result z-score Result z-score Result z-score Result z-score

Lab code µg/kg µg/kg µg/kg µg/kg µg/kg

101 2,5 -0,5 2,2 -0,1 4,6 -0,7 2,7 -0,1 12 -0,8

102 2,14 -1,1 1,88 -0,8 4,707 -0,6 1,989 -1,4 10,716 -1,7

103 3,1 0,5 2,3 0,1 6 0,6 3,1 0,6 14,5 0,9

104 2,58 -0,4 2,25 0,0 5,25 -0,1 2,67 -0,2 12,75 -0,3

105 2,7 -0,2 2 -0,6 4,5 -0,8 2,8 0,1 12,1 -0,7

106 2,84 0,1 2,32 0,1 4,65 -0,6 2,76 0,0 12,57 -0,4

107 2,27 -0,9 1,87 -0,8 4,44 -0,8 2,45 -0,6 11,03 -1,5

108 3,21 0,7 2,42 0,3 5,43 0,1 3,05 0,5 14,1 0,7

109 2,58 -0,4 2,14 -0,3 4,95 -0,3 2,98 0,4 12,65 -0,3

110 2,83 0,1 2,36 0,2 5,79 0,4 2,31 -0,8 13,3 0,1

111 2,18 -1,1 2,1 -0,4 3,72 -1,5 2,51 -0,5 10,5 -1,9

112 2,9 0,2 2,2 -0,1 5,3 0,0 3 0,4 13,5 0,2

113 1,42 -2,4 2,37 0,2 2,33 -2,8 2,7 -0,1 8,82 -3,0

114 3,1 0,5 2,73 1,0 8,57 3,0 3,37 1,1 17,77 3,2

115 3,79 1,7 2,81 1,1 6,33 0,9 3,83 1,9 16,76 2,5

116 2,76 -0,1 2,47 0,4 6,28 0,9 2,83 0,1 14,34 0,8

117 2,3 -0,8 2 -0,6 4,7 -0,6 2,5 -0,5 11 -1,5

118 2,5 -0,5 2,14 -0,3 4,66 -0,6 2,44 -0,6 11,73 -1,0

119 3,01 0,4 2,34 0,1 5,49 0,2 2,69 -0,1 13,53 0,3

120 3,01 0,4 2,54 0,6 5,5 0,2 2,81 0,1 13,86 0,5

121 2,85 0,1 2,45 0,4 5,44 0,1 2,86 0,2 13,6 0,3

122 3,03 0,4 2,48 0,4 5,93 0,6 3,04 0,5 14,48 0,9

123 3,14 0,6 2,41 0,3 5,35 0,0 3,42 1,1 14,33 0,8

124 2,84 0,1 2,17 -0,2 5,13 -0,2 3,3 0,9 13,4 0,2

515 2,1 -1,2 1,7 -1,2 4,1 -1,1 2,1 -1,2 10 -2,2

501 3,037 0,4 1,85 -0,9 4,967 -0,3 2,873 0,2 12,727 -0,3

502 2,781 0,0 2,048 -0,5 4,438 -0,8 2,496 -0,5 11,763 -1,0

503 2,57 -0,4 2,54 0,6 7,94 2,4 4,2 2,5 17,25 2,9

504 3,6 1,4 2,12 -0,3 5,29 0,0 2,89 0,2 13,89 0,5

505 3,01 0,4 3,23 2,0 5,4 0,1 3,11 0,6 14,72 1,1

506 2,21 -1,0 1,99 -0,6 5,77 0,4 3,54 1,4 13,62 0,3

507 2,9 0,2 2,31 0,1 5,47 0,1 3,01 0,4 13,69 0,4

508 2,5 -0,5 2,5 0,5 5,2 -0,1 2,6 -0,3 12,8 -0,2

509 3,1 0,5 2,46 0,4 5,8 0,4 3,3 0,9 14,7 1,1

510 2 -1,4 2 -0,6 2,9 -2,3 2,3 -0,8 9,2 -2,8

511 2,5 -0,5 2,11 -0,3 6,47 1,1 2,31 -0,8 13,39 0,2

512 2,7 -0,2 2,2 -0,1 4,8 -0,5 2,9 0,2 12,7 -0,3

513 2,32 -0,8 1,87 -0,8 4,94 -0,4 2,44 -0,6 11,57 -1,1

514 3,13 0,6 2,55 0,6 5,72 0,4 3,26 0,9 14,66 1,1

516 5,58 4,8 3,04 1,6 8,45 2,9 7,84 8,9 24,91 8,2

517 2,44 -0,6 2,06 -0,4 5,2 -0,1 2,21 -1,0 11,9 -0,9

518 2,8 0,0 2,4 0,3 5,3 0,0 2,8 0,1 13,3 0,1

CHR

0,58 0,48 1,07 0,57

BAA BAP BBF

Official control laboratories (OCLs)

1,43

2,79 2,27 5,32 2,77 13,15

National Reference Laboratories (NRLs)

16

Table 6: Compilation of zeta-scores calculated from the “results for proficiency assessment" reported by the NRLs and OCLs for test material OIL, the combined reported standard measurement uncertainty, and the uncertainty of the analyte content of the test material:

zeta-Scores outside the satisfactory range (|zeta| > 2) are highlighted in red. Yellow highlighted cells indicate measurement uncertainty values that either did not comply with the thresholds given by the "fitness-for-purpose" function Uf (BAA, BAP, BBF, and CHR), or were not in agreement with the uncertainty value derived from the uncertainties of the individual analytes (SUM parameter).

Assigned value +/- U, µµµµg/kg

2,79 ± 0,02 2,27 ± 0,03 5,32 ± 0,05 2,77 ± 0,03 13,15 ± 0,07

σσσσρ, µρ, µρ, µρ, µg/kgResult U zeta-

scoreResult U zeta-

scoreResult U zeta-

scoreResult U zeta-

scoreResult U zeta-

scoreLab code µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg µµµµg/kg

101 2,5 0,49 -1,2 2,2 0,44 -0,3 4,6 0,92 -1,6 2,7 0,54 -0,3 12 1,3 -1,8102 2,14 0,719 -1,8 1,88 0,523 -1,5 4,707 1,214 -1,0 1,989 0,551 -2,8 10,716 3,007 -1,6103 3,1 0,6 1,0 2,3 0,5 0,1 6 1,2 1,1 3,1 0,7 0,9 14,5 1,6 1,7104 2,58 0,67 -0,6 2,25 0,77 -0,1 5,25 1,57 -0,1 2,67 0,59 -0,3 12,75 1,97 -0,4105 2,7 0,54 -0,3 2 0,4 -1,3 4,5 0,9 -1,8 2,8 0,56 0,1 12,1 1,2 -1,7106 2,84 0,48 0,2 2,32 0,35 0,3 4,65 0,65 -2,1 2,76 0,44 0,0 12,57 2,14 -0,5107 2,27 0,31 -3,3 1,87 0,25 -3,2 4,44 0,5 -3,5 2,45 0,72 -0,9 11,03 0,96 -4,4108 3,21 0,72 1,2 2,42 0,45 0,7 5,43 0,9 0,2 3,05 0,84 0,7 14,1 2,83 0,7109 2,58 0,45 -0,9 2,14 0,43 -0,6 4,95 1,03 -0,7 2,98 0,52 0,8 12,65 4,82 -0,2110 2,83 0,58 0,1 2,36 0,48 0,4 5,79 1,17 0,8 2,31 0,49 -1,9 13,3 1,47 0,2111 2,18 0,14 -8,6 2,1 0,14 -2,4 3,72 0,62 -5,1 2,51 0,47 -1,1 10,5 0,8 -6,6112 2,9 0,6 0,4 2,2 0,5 -0,3 5,3 1,7 0,0 3 0,5 0,9 13,5 1,9 0,4113 1,42 0,2 -13,6 2,37 0,38 0,5 2,33 0,35 -16,9 2,7 0,45 -0,3 8,82 0,71 -12,1114 3,1 0,99 0,6 2,73 0,66 1,4 8,57 1,2 5,4 3,37 0,71 1,7 17,77 1,83 5,0115 3,79 0,38 5,3 2,81 0,28 3,8 6,33 0,63 3,2 3,83 0,38 5,6 16,76 0,88 8,2116 2,76 0,7 -0,1 2,47 0,6 0,7 6,28 1,6 1,2 2,83 0,7 0,2 14,34 3,6 0,7117 2,3 0,69 -1,4 2 0,6 -0,9 4,7 1,41 -0,9 2,5 0,75 -0,7 11 6,6 -0,7118 2,5 0,28 -2,1 2,14 0,35 -0,7 4,66 0,68 -1,9 2,44 0,28 -2,3 11,73 2,06 -1,4119 3,01 0,45 1,0 2,34 0,3 0,5 5,49 0,88 0,4 2,69 0,38 -0,4 13,53 3,94 0,2120 3,01 0,23 1,9 2,54 0,2 2,7 5,5 0,52 0,7 2,81 0,3 0,3 13,86 0,67 2,1121 2,85 0,43 0,3 2,45 0,24 1,5 5,44 0,82 0,3 2,86 0,36 0,5 13,6 1,02 0,9122 3,03 0,48 1,0 2,48 0,44 1,0 5,93 1,02 1,2 3,04 0,5 1,1 14,48 1,31 2,0123 3,14 0,202 3,4 2,41 0,173 1,6 5,35 0,056 0,8 3,42 0,075 16,1 14,33 0,282 8,1124 2,84 0,1 1,0 2,17 0,2 -1,0 5,13 0,4 -0,9 3,3 0,2 5,2 13,4 1,3 0,4515 2,1 0,9 -1,5 1,7 0,7 -1,6 4,1 1,7 -1,4 2,1 0,9 -1,5 10 4,2 -1,5

501 3,037 n.r. 1,85 n.r. 4,967 n.r. 2,873 n.r. 12,727 n.r.502 2,781 0,5562 0,0 2,048 0,4096 -1,1 4,438 0,8876 -2,0 2,496 0,4992 -1,1 11,763 2,3526 -1,2503 2,57 0,9 -0,5 2,54 0,89 0,6 7,94 2,78 1,9 4,2 1,47 1,9 17,25 3,39 2,4504 3,6 0,54 3,0 2,12 0,32 -0,9 5,29 0,79 -0,1 2,89 0,43 0,6 13,89 2,08 0,7505 3,01 0,78 0,6 3,23 0,84 2,3 5,4 1,43 0,1 3,11 0,81 0,8 14,72 2 1,6506 2,21 0,63 -1,8 1,99 0,6 -0,9 5,77 1,24 0,7 3,54 0,84 1,8 13,62 1,73 0,5507 2,9 0,6 0,4 2,31 0,5 0,2 5,47 1 0,3 3,01 0,6 0,8 13,69 3 0,4508 2,5 0,5 -1,2 2,5 0,375 1,2 5,2 15 -0,3 2,6 0,52 -0,7 12,8 2,56 -0,3509 3,1 0,6 1,0 2,46 0,49 0,8 5,8 1,2 0,8 3,3 0,7 1,5 14,7 2,9 1,1510 2 0,8 -2,0 2 0,9 -0,6 2,9 1 -4,8 2,3 0,9 -1,0 9,2 3,6 -2,2511 2,5 0,64 -0,9 2,11 0,53 -0,6 6,47 1,64 1,4 2,31 0,59 -1,6 13,39 1,93 0,2512 2,7 0,6 -0,3 2,2 0,7 -0,2 4,8 1 -1,0 2,9 0,6 0,4 12,7 1,5 -0,6513 2,32 0,28 -3,3 1,87 0,36 -2,2 4,94 0,59 -1,3 2,44 0,46 -1,4 11,57 2,2 -1,4514 3,13 0,66 1,0 2,55 0,51 1,1 5,72 1,2 0,7 3,26 0,65 1,5 14,66 1,6 1,9516 5,58 n.r. 3,04 n.r. 8,45 n.r. 7,84 n.r. 24,91 n.r.517 2,44 0,52 -1,3 2,06 0,42 -1,0 5,2 1 -0,2 2,21 0,47 -2,4 11,9 2,5 -1,0518 2,8 0,4 0,0 2,4 0,2 1,3 5,3 1,7 0,0 2,8 0,3 0,2 13,3 n.r. 6,3

BBF CHR

1,43

SUM

Official Control Laboratories (OCLs)

0,58 0,48 1,07 0,57

National Reference Laboratories (NRLs)

BAA BAP

n.r.: not reported

17

average repeatability standard deviation of the results reported by the participants along the y-axis. The latter was obtained by analysis-of-variance of the data set received for each analyte.

Participants whose data are outside the satisfactory performance area should perform root cause analysis. It would be very much appreciated if they would report back to the EU-RL PAH the identified reason for the deviations.

9.4 Additional information extracted from the questionnaire Additional information was gathered from the questionnaire filled in by the participants (ANNEX 7). Data is presented as reported.

Regarding the experience of the laboratories with this kind of analysis 38 laboratories reported experience of more then one year, 1 laboratory - less then one year and 2 laboratories didn't respond. The distribution in terms of years experience and number of analysis per year between NRLs and OCLs is shown in Figure 3 and 4.

Eighty four percents of the NRLs and 81 percents of OCLs are accredited for the methods of analysis used in this exercise (Figure 5).

More than half of the participants (NRLs and OCLs) used GC/MS (GC/MSMS or HRMS) techniques for performing analysis, while 31% of NRLs and 40% of OCLs applied HPLC/FLD (Figure 6). The analysis of all data revealed that laboratory performance was not linked to any analytical technique or sample preparation method used.

Figure 3. Experience of NRLs (a) and OCLs (b) in years in the analysis of PAH in edible oil

22

7

13

01

< 1

1 - 4

5 - 8

9 - 15

> 15

no response

NRL

EXPERIENCE [years]

021

5

8

0

< 1

1 - 4

5 - 8

9 - 15

> 15

no response

OCL

EXPERIENCE [years]

Figure 4. Experience of NRLs (a) and OCLs (b) in the analysis of PAH in edible oil expressed as number of analysis per years

7

9

4

32

< 10

10 - 50

51 - 100

> 100

no response

NRL

SAMPLE / YEAR

0

8

5

1 0

< 10

10 - 50

51 - 100

> 100

no response

OCL

SAMPLE / YEAR

18

Figure 5. Accreditation of NRLs (a) and OCLs (b) for the methods of analysis used in this PT

2

2

21

YES

NO

no response

NRL

ACCREDITATION

13

3

0

YES

NO

no response

OCL

ACCREDITATION

Figure 6. Application of different instrumental methods for determination of PAH in edible oil.

13

8

2

1

2

0

GC/MS

HPLC/FLD

GC/MSMS

GC/HRMS

HPLC/MS

HPLC

NRL

ANALITICAL METHODS

010

0

6

8

GC/MS

HPLC/FLD

GC/MSMS

GC/HRMS

HPLC/MS

HPLC

OCL

ANALITICAL METHODS

Finally, ANNEX 7 summarises the comments of the participants regarding the organised interlaboratory comparison.

10. Follow-up actions for underperforming laboratories

All NRL laboratories that got "questionable" or "non-satisfactory" performance ratings are urged to perform root cause analysis, and to implement corrective actions.

The EU-RL will set up follow-up measures in due time for all NRLs that received for at least one of the four PAHs (BAA, BAP, BBF, and CHR) z-scores > |3| as required by Regulation (EC) 882/2004, and by the Protocol for management of underperformance in comparative testing and/or lack of collaboration of National Reference Laboratories (NRLs) with European Union reference laboratories (EU-RLs) activities. These laboratories shall perform as an immediate action root-cause-analysis, and shall report to the EU-RL PAH in writing the identified cause for their underperformance and corrective actions they are going to take. Additionally, they shall participate to an independent (non-EU-RL) proficiency test on the determination of PAHs in food and shall communicate the outcome of this exercise to the EU-RL PAH.

11. Conclusions

Forty-two participants reported analysis results. The performance of most participants was good. In total 94.4 and 90.5 of the results reported by NRLs and OCLs respectively obtained a satisfactory z-score. zeta-Scores were calculated besides z-scores. They indicate the agreement of the reported result with the assigned value with respect to the stated measurement uncertainty. The outcome of this rating was worse than for the z-scores, which reveals that the measurement uncertainty estimates were in some cases not realistic.

19

12. Acknowledgements

The organizers would like to thank Beatriz de la Calle and Franz Ulberth (all from IRMM, Geel, Belgium) for their accurate revision of this report and all NRLs and OCLs for their cooperation.

13. References

i EU, COMMISSION REGULATION (EC) No 776/2006 of 23 May 2006 amending Annex VII to Regulation

(EC) No 882/2004 of the European Parliament and of the Council as regards Community reference laboratories. Official Journal of the European Union, 2006. L 136: p. 3-8. Available from:

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:136:0003:0008:EN:PDF

ii EU, Regulation (EC) No 882/2004 of the European Parliament and of the Council of 29 April 2004 on official controls performed to ensure the verification of compliance with feed and food law, animal health and animal welfare rules. Official Journal of the European Communities, 2004. L191: p. 1-52. Available from:


iii EU, Opinion of the Scientific Committee on Food on the risks to human health of Polycyclic Aromatic Hydrocarbons in food. (2002). Available from:

http://europa.eu.int/comm/food/fs/sc/scf/out153_en.pdf

iv IARC. Overall Evaluations of Carcinogenicity to Humans. IARC Monographs on the Evaluation of Carcinogenic Risks to humans (2006). Available from:

http://monographs.iarc.fr/ENG/Classification/crthgr01.php

v EU, Commission Recommendation (2005/108/EC) of 4 February 2005 on the further investigation into the levels of polycyclic aromatic hydrocarbons in certain foods. Official Journal of the European Union, 2005. L 34: p. 43-45. Available from:


vi EU, Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. Official Journal of the European Union, 2006. L 364: p. 5-24. Available from:

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:364:0005:0024:EN:PDF Amended by Regulation (EU) No 835/2011 which applies from 1 September 2012. Official Journal of the

European Union, 2011. L 215: p. 4-8

vii EU, Commission Regulation (EC) No 333/2007 of 28 March 2007 laying down the methods of sampling and analysis for the official control of the levels of lead, cadmium, mercury, inorganic tin, 3-MCPD and benzo(a)pyrene in foodstuffs. Official Journal of the European Union, 2007. L 88: p. 29-38. Available from:

http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:088:0029:0038:EN:PDF Amended by Regulation (EU) No 836/2011 which applies from 1 September 2012. Official Journal of the

European Union, 2011. L 215: p. 9-16

viii EFSA, Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the European Commission on Polycyclic Aromatic Hydrocarbons in Food. The EFSA Journal, 2008. 724: p. 1-114. Available from:

http://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1211902034842.htm

ix ISO/IEC 17043:2010 (2010). Conformity assessment -- General requirements for proficiency testing providers. Geneva, Switzerland

x Evaluation of measurement data – Guide to the expression of uncertainty in measurement JCGM 100:2008 (GUM 1995 with minor corrections)

20

14. ANNEXES

ANNEX 1 – Announcement of the PT on the IRMM webpage

ANNEX 2 – Announcement via e-mail and invitation

ANNEX 3 – Announcement of material dispatch

ANNEX 4 – Documents sent to participants

ANNEX 5 – Technical specifications of the calibration solutions

ANNEX 6 – Homogeneity of the test material

ANNEX 7 – Questionnaire

ANNEX 8 – Data reported by participants

ANNEX 9 - Laboratory means and repeatability standard deviation

21

ANNEX 1: Announcement of the PT on the IRMM webpage

22

ANNEX 2: Announcement of the PT via invitation

24

ANNEX 3: Announcement of material dispatch

25

ANNEX 4: Documents sent to participants - OUTLINE

27

INSTRUCTIONS

29

SAMPLE RECEIPT

30

PARTICIPANT CODES

31

ANNEX 5: Technical specifications of the calibration solutions

32

ANNEX 6: Homogeneity of the test material

Analyte: BAA

n = 10mean = 3.0455 21% = σ-trg(%)

0.032880278 sx = 0.1813 0.6414 = σ-trg

ÖMSW = sw = 0.1913

ss = 0.1208 0.1924 = 0,3*s

ISO-13528 passed

F = 0 3.02038295 = Fcritpassed

IUPAC

(MSB-MSW)/2 0.0146 0.1066= F1*(0,3*s)2+F2*MSWpassed

Bottle Result a Result b diff sum avgAmpoule 020 3.36 3.34 0.02 6.7 3.35Ampoule 026 3.07 3.4 -0.33 6.47 3.235Ampoule 039 3.22 2.95 0.27 6.17 3.085Ampoule 077 2.95 2.89 0.06 5.84 2.92Ampoule 095 2.95 3.27 -0.32 6.22 3.11Ampoule 102 2.88 2.91 -0.03 5.79 2.895Ampoule 120 3.33 3.02 0.31 6.35 3.175Ampoule 159 3.32 2.79 0.53 6.11 3.055Ampoule 174 2.92 2.72 0.2 5.64 2.82Ampoule 187 2.73 2.89 -0.16 5.62 2.81

∑(diff) 2 = 0.7317var(sum)/2 = 0.06576 =MSB

2.5

2.65

2.8

2.95

3.1

3.25

3.4

3.55

3.7

3.85

4

Analyte: BAP

n = 10mean = 2.6485 21% = σ-trg(%)

0.017116944 sx = 0.1308 0.5578 = σ-trg

ÖMSW = sw = 0.1814

ss = 0.0259 0.1673 = 0,3*s

ISO-13528 passed


IUPAC


Bottle Result a Result b diff sum avgAmpoule 020 2.77 2.94 -0.17 5.71 2.855Ampoule 026 2.5 2.93 -0.43 5.43 2.715Ampoule 039 2.79 2.6 0.19 5.39 2.695Ampoule 077 2.49 2.53 -0.04 5.02 2.51Ampoule 095 2.55 2.88 -0.33 5.43 2.715Ampoule 102 2.5 2.59 -0.09 5.09 2.545Ampoule 120 2.91 2.61 0.3 5.52 2.76Ampoule 159 2.93 2.49 0.44 5.42 2.71Ampoule 174 2.57 2.5 0.07 5.07 2.535Ampoule 187 2.46 2.43 0.03 4.89 2.445

∑(diff) 2 = 0.6579var(sum)/2 = 0.03423 =MSB

2

2.15

2.3

2.45

2.6

2.75

2.9

3.05

3.2

3.35

3.5

33

Analyte: BBF

n = 10mean = 5.8080 20% = σ-trg(%)

0.109156667 sx = 0.3304 1.1732 = σ-trg

ÖMSW = sw = 0.3751

ss = 0.1970 0.3520 = 0,3*s

ISO-13528 passed


IUPAC


Bottle Result a Result b diff sum avgAmpoule 020 6.37 6.41 -0.04 12.78 6.39Ampoule 026 5.77 6.48 -0.71 12.25 6.125Ampoule 039 6.14 5.6 0.54 11.74 5.87Ampoule 077 5.59 5.51 0.08 11.1 5.55Ampoule 095 5.67 6.22 -0.55 11.89 5.945Ampoule 102 5.55 5.56 -0.01 11.11 5.555Ampoule 120 6.33 5.7 0.63 12.03 6.015Ampoule 159 6.4 5.28 1.12 11.68 5.84Ampoule 174 5.55 5.34 0.21 10.89 5.445Ampoule 187 5.29 5.4 -0.11 10.69 5.345

∑(diff) 2 = 2.8138var(sum)/2 = 0.21831 =MSB

5

5.2

5.4

5.6

5.8

6

6.2

6.4

6.6

6.8

7

Analyte: CHR

n = 10mean = 3.0490 21% = σ-trg(%)

0.044215556 sx = 0.2103 0.6318 = σ-trg

ÖMSW = sw = 0.2128

ss = 0.1469 0.1895 = 0,3*s

ISO-13528 passed


IUPAC


Bottle Result a Result b diff sum avgAmpoule 020 3.39 3.45 -0.06 6.84 3.42Ampoule 026 3.09 3.44 -0.35 6.53 3.265Ampoule 039 3.35 2.93 0.42 6.28 3.14Ampoule 077 2.83 2.84 -0.01 5.67 2.835Ampoule 095 2.95 3.22 -0.27 6.17 3.085Ampoule 102 2.85 2.92 -0.07 5.77 2.885Ampoule 120 3.32 3.05 0.27 6.37 3.185Ampoule 159 3.35 2.75 0.6 6.1 3.05Ampoule 174 2.97 2.7 0.27 5.67 2.835Ampoule 187 2.72 2.86 -0.14 5.58 2.79

∑(diff) 2 = 0.9058var(sum)/2 = 0.08843 =MSB

2.5

2.65

2.8

2.95

3.1

3.25

3.4

3.55

3.7

3.85

4

34

ANNEX 7: Questionnaire

BLANK TEMPLATE

36

QUESTIONNAIRE: On the organisation of the PT

• Did you find the instructions distributed for this PT adequate? • If NO, please report about possible lacking information (for NRLs no matching case) • Did you experience any specific problem related to the organisation of this PT? • If YES, please describe here the main problems you were confronted with (e.g. registration, reporting of

results, questionnaire, content of the parcel, material quantity/stability/packaging, instructions concerning the samples, etc)

• In the following field you may add any further information about this PT and the analysis of the samples

NRLs

LabID Instructions adequate

Lacking information

Organisation problems

Organisation problems description

Additional comments

101 a) Yes b) no b) no b) no









110 a) Yes b) no a) yes

The communication of the error happened to late, which caused an extra time consumption. b) no





115 a) Yes b) no a) yes The change of standard solution specification sheet b) no

116








124


37

OCLs

LabID Instructions adequate

Organisation problems

Organisation problems description Additional comments

501 a) Yes b) no b) no

















38

On participants profile • Did your laboratory quantify PAHs in EDIBLE OIL before? • If YES, for how long? (expressed in years) - If OTHER, please specify • If YES, how many samples per year does your laboratory analyse for THIS FOOD CATEGORY? - If

OTHER, please specify • Is your laboratory accredited for the determination of PAHs in food? • If YES, please specify the food matrix included in the accreditation scope - If OTHER, please specify -

If you chose "the following of the matrices listed above", please report the corresponding codes • If YES, please specify the PAHs included in the accreditation scope - If OTHER, please specify

NRLs

LabID

Analysis of PAHs in Edible oil

For how long (years)

Samples / year Accredited Matrices in

accreditation scope Analytes in accreditation scope

101 a) yes c) 4-8 d) > 100 a) yes 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, c) 15+1 EU priority PAHs

102 a) yes c) 4-8 a) < 10 a) yes 6.1.1 c) 15+1 EU priority PAHs

103 a) yes c) 4-8 b) 10-50 b) no true true

104 a) yes d) 8-15 d) > 100 a) yes 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.7, 6.1.8 c) 15+1 EU priority PAHs

105 a) yes

only previous proficiency test with LC-MS otherwise use of GC-MS for 4 years a) < 10 a) yes

6.1.1.+6.1.2+6.1.3+6.1.4+6.1.6+6.1.7

15+1 EUpriority PAHs + acenaphthene, acenaphthylene,fluorene, fluoranthene, pyrene, anthracene, benzo(e)pyrene

106 a) yes d) 8-15 a) < 10 a) yes 6.1.1, 6.1.2, 6.1.3, 6.1.7, 6.1.8 c) 15+1 EU priority PAHs

107 a) yes c) 4-8 a) < 10 a) yes 6.1.1, 6.1.2, 6.1.3 b) 4 marker PAHs

108 a) yes c) 4-8 a) < 10 a) yes

6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9 c) 15+1 EU priority PAHs

109 a) yes c) 4-8 b) 10-50 a) yes


110 a) yes d) 8-15 c) 50-100 a) yes

6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9

15+1 EU priority PAHs plus Phenanthrene, Anthracene, Pyrene, Fluoranthene, Benzo(e)pyrene

111 a) yes c) 4-8 b) 10-50 a) yes 6.1.1, 6.1.2, 6.1.3,6.1.4.6.1.7,6.1.8, c) 15+1 EU priority PAHs

112 a) yes c) 4-8 b) 10-50 a) yes 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.7, 6.1.8, EU priority 15

113 a) yes d) 8-15 a) < 10 a) yes 6.1.1 a) BaP

114 a) yes c) 4-8 b) 10-50 a) yes 6.1.1, 6.1.2 b) 4 marker PAHs

115 a) yes c) 4-8 c) 50-100 a) yes 6.1.1, 6.1.2, 6.1.3 a) BaP

116

117 a) yes a) <1 a) < 10 b) no true

118 a) yes c) 4-8 b) 10-50 a) yes


119 a) yes e) >15 c) 50-100 a) yes 6.1.1 6.1.2 6.1.3 6.1.4 c) 15+1 EU priority PAHs

120 a) yes d) 8-15 b) 10-50 a) yes

6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9

15+1 EU priority PAHs excluding Benzo(c)fluorene

121 a) yes c) 4-8 b) 10-50 a) yes

6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9

24 PAHs including 15 EU priority PAHs (not accredited for Benzo(c)fluorene)

39

LabID

Analysis of PAHs in Edible oil


Samples / year Accredited Matrices in

accreditation scope Analytes in accreditation scope

122 a) yes d) 8-15 c) 50-100 a) yes

6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9

28 PAHs including the above.

123 a) yes d) 8-15 b) 10-50 a) yes 6.1.1 c) 15+1 EU priority PAHs

124

515 a) yes e) >15 d) > 100 a) yes 6.1.1 c) 15+1 EU priority PAHs

OCLs

LabID PAHs in Edible oil


Samples / year Accredited

Matrices in accreditation scope

Analytes in accreditation scope

501 a) yes b) 1-4 a) < 10 b) no true true

502 a) yes b) 1-4 c) 50-100 a) yes 6.1.1 c) 15+1 EU priority PAHs

503 b) no true true a) yes 6.1.2 a) BaP

504 a) yes b) 1-4 a) < 10 a) yes foodstuffs, raw materials e) other

505 a) yes b) 1-4 a) < 10 a) yes 6.1.1.,6.1.2.,6.1.3.,6.1.4. b) 4 marker PAHs

506 a) yes c) 4-8 a) < 10 a) yes 6.1.2, 6.1.3 b) 4 marker PAHs

507 a) yes c) 4-8 b) 10-50 a) yes 6.1.5 c) 15+1 EU priority PAHs

508 a) yes c) 4-8 b) 10-50 a) yes


509 a) yes e) >15 b) 10-50 a) yes


510 a) yes b) 1-4 c) 50-100 a) yes 6.1.1 b) 4 marker PAHs

511 a) yes d) 8-15 c) 50-100 b) no true true

512 a) yes b) 1-4 b) 10-50 a) yes 6.1.1 b) 4 marker PAHs

513 a) yes b) 1-4 b) 10-50 a) yes 6.1.1, 6.1.2, 6.1.3, b) 4 marker PAHs

514 a) yes e) >15 b) 10-50 a) yes 6.1.1, 6.1.2,6.1.3,6.1.4,6.1.5, b) 4 marker PAHs

516 a) yes b) 1-4 b) 10-50 b) no true true

517 a) yes c) 4-8 a) < 10 a) yes 6.1.1 e) other

518 a) yes c) 4-8 c) 50-100 a) yes 6.1.7 e) other

Food categories as listed in Regulation (EC) No 1881/2006: Crustaceans, cephalopods, other than smoked (6.1.5) Oils and fats (6.1.1) Bivalve molluscs (6.1.6) Smoked meats and smoked meat products (6.1.2) Processed cereal-based foods and baby foods for infants and

young (6.1.7) Muscle meat of smoked fish and smoked fishery products (6.1.3) Infant formulae and follow-on formulae (6.1.8)

Muscle meat of fish (6.1.4) Dietary foods for special medical purposes (6.1.9)

Food categories as listed in Regulation (EC) No 1881/2006: Crustaceans, cephalopods, other than smoked (6.1.5) Oils and fats (6.1.1) Bivalve molluscs (6.1.6) Smoked meats and smoked meat products (6.1.2) Processed cereal-based foods and baby foods for infants and

young (6.1.7) Muscle meat of smoked fish and smoked fishery products (6.1.3) Infant formulae and follow-on formulae (6.1.8)

Muscle meat of fish (6.1.4) Dietary foods for special medical purposes (6.1.9)

40

On the method applied • How did you prepare the sample? • Which extraction method did you use? • Which was the MAIN purification step of your method? • Which was the instrumental detection method you applied? • Please describe the analytical column used • Did you encounter any problems during the analysis of the sample?

NRLs

LabID Preparation Extraction Purification Detection Column Problems

101 a) Dilution d) No extraction b) Size-Exclusion Chromatography a) HPLC-FLD

501 TP 54 GRACE 250 x 4,6 mm b) No

102 a) Dilution liquid-liquid extraction

a) Donor-Acceptor Complex Chromatography (DACC)

c) HPLC-FLD-UV

agilent zorbax eclipse plus c18 3.5µm 100X4.6mm b) No

103 b) No preparation

b) Pressurized liquid extraction

c) Solid Phase Extraction (SPE)

c) HPLC-FLD-UV

Grace Vydac, C18 250x4.6 mm, 5um b) No


Waters PAH C18, 5um, 3x250mm b) No

105

addition of internal standard (ISTD) d) No extraction

b) Size-Exclusion Chromatography e) HPLC-MS

Zorbax Eclipse PAH 2.1x50mm, 1.8µ

Addition of ISTD at different concentration than calibration curve, corrected.

106 a) Dilution d) No extraction b) Size-Exclusion Chromatography j) GC-MS

ZB-35, 30m, 0.25 mm i.d., 0.25 um b) No

107 a) Dilution d) No extraction c) Solid Phase Extraction (SPE) l) GC-MS/MS

Agilent Select PAH, 30 m, 0,25 mm, 0,15 µm b) No


Varian Select PAH, 30m x 0.25mm x 0.15 µm b) No

109 a) Dilution liquid/liquid-extraction

b) Size-Exclusion Chromatography j) GC-MS

OPTIMA 35 MS, 30m; 0,25mm; 0.25 µm b) No

110

liquid/liquid partition and SPE

liquied/liquid extraction


HPLC-FLD plus GC-MS

Select PAH, 30 m, 0.25 mm, 0.25 µ

Unclear FLD spectrum of chrysene obliged us to use an alternative technique. This may frequently occure in olive oils.


SELECTPAH 15*0,15*0,10 b) No

112 b) No preparation a) Saponification

d) Solvent partitioning j) GC-MS

5% phenylmethyl 60m x 0.25mm x 0.25µ b) No

113 a) Dilution d) No extraction SPE-MIP j) GC-MS

DB 17 30m x 0.25mm x 0.15 um (50 % Phenyl) - methylpolysilossane b) No

114 a) Dilution liquid/liquid partitioning

c) Solid Phase Extraction (SPE) j) GC-MS

Select PAH (30m×0,25mm×0,15µm) b) No

115

Saponification, liquid/liquid extraction, chromatography/fractionation a) Saponification

d) Solvent partitioning a) HPLC-FLD

LiChroCART 250-4, LiChrosper PAH (5µm) b) No

116


b) Pressurized liquid extraction

c) Solid Phase Extraction (SPE) l) GC-MS/MS

Varian GC Capillary column, Select PAH -15m x0,15mm ID DF=0,10 um b) No


Liquid/liquid extraction with ACN/acetone


c) HPLC-FLD-UV

C18 (PAH specific), 250 x 4,6 mm, 5 um, Agilent PAH Pursuit b) No

41

LabID Preparation Extraction Purification Detection Column Problems


PAH C18 5um; 4,6x250mm, 5 µm (Waters P/N 186001265) b) No


PAH C18, 5µm, 250 x 4.6 mm,

Apparently there is a discrepancy between the provided 4-PAH standard and our own 15+1 PAH standard. We have carrried out some recovery experiments and our conclusion was that the real concentrations of the provided 4-PAH standard were lower that the reported concentrations. The analysis of a RM of olive oil (FAPAS ref.T0636) gave recoveries of > 150 % when using the provided 4-PAH standard.



DB 35ms, 30m, 0.25 mm, 0.15µm b) No


d) Solvent partitioning j) GC-MS

PAH Select 30m (Varian) b) No

123 a) Dilution d) No extraction b) Size-Exclusion Chromatography k) GC-HRMS

Varian PAH-select, 30m x 0.25 mm x 0.15 µm and DB5-MS, 60 m x 0.25 mm x 0.25 µm

Suppression of benzo[a]anthracene signal on PAH-select column,for this PAH was therefor the DB5-MS column was used. No suppression problem with that column.

124

515 c) Other liquid-liquid extraction


SELECT PAH (30m x 0.25mm x 0.15um) b) No

42

OCLs LabID Preparation Extraction Purification Detection Column Problems

501 a) Dilution a) Saponification d) Solvent partitioning j) GC-MS

Agilent DB-EUPAH; 20mx0,180mm*0,14µm b) No


Reversed phase C18, 5µm, 150 x 4.6mm b) No

503 b) No preparation a) Saponification d) Solvent partitioning a) HPLC-FLD

LichroCHART 5µ 250 X 3mm b) No

504 b) No preparation liquid extraction b) Size-Exclusion Chromatography a) HPLC-FLD

Waters PAH C18 Column, 120Å, 5 µm, 4.6 mm X 250 mm b) No

505 a) Dilution d) No extraction e) Other a) HPLC-FLD WATERS PAH (250mm x 4.6 mm x 5 um) b) No

506 HCl hydrolysis liquid-liquid extraction e) Other a) HPLC-FLD

Vudac Grase C18, 150x4.6mm 5um b) No

507 LYOPHILISATION

EXTRACTION SOUS PRESSION TYPE ASE

c) Solid Phase Extraction (SPE) l) GC-MS/MS

5% polysilarylène -95% polydimethylsiloxane 20M X 0.25mm x 0.25µm b) No

508 b) No preparation b) Pressurized liquid extraction

c) Solid Phase Extraction (SPE) l) GC-MS/MS b) No

509 b) No preparation a) Saponification b) Size-Exclusion Chromatography l) GC-MS/MS

Select PAH (30mx250µmx0,15µm). Agilent b) No

510 extraction KOH; liquid to liquid


15m Varian Select PAH; 0,15 mm; 0,1 µm b) No

511 b) No preparation b) Pressurized liquid extraction

b) Size-Exclusion Chromatography l) GC-MS/MS

TR-5MS length 30 m ID 0.25 mm film thickness 0.25 um b) No

512 a) Dilution d) No extraction b) Size-Exclusion Chromatography j) GC-MS

DB-EUPAH, 20 m, 0.180 mm, 0.14 µm b) No

513 a) Dilution d) No extraction c) Solid Phase Extraction (SPE) a) HPLC-FLD

Agilent Eclipse PAH 50x4.6mm 1.8um b) No

514 a) Dilution b) Pressurized liquid extraction e) Other a) HPLC-FLD

Lichrocard, PAH, 5um, 250-4mm b) No

516 a) Dilution SPE extraction c) Solid Phase Extraction (SPE) j) GC-MS

5%phenyl-95%dimethyl polixyloxane, 30 m x 0.25mm x 0.15um b) No

517 a) Dilution FILTER e) Other a) HPLC-FLD Inertsil-P ODS-P 250 mm x 4,6 mm i.d, 5 um b) No

518 a) Dilution d) No extraction

a) Donor-Acceptor Complex Chromatography (DACC) c) HPLC-FLD-UV Varian Pursuit PAH b) No

43

ANNEX 8: Data reported by participants

The data reported by the participants are compiled in the following tables. The results of replicate analyses together with the expanded measurement uncertainty (k=2) reported for the value for proficiency assessment are depicted in the graphs. Red lines indicate the thresholds for satisfactory z-scores. Results reported by NRLs for the content of benz[a]anthracene (BAA) in the olive oil test material. Assigned value is 2.79 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]

Value for proficiency assessment

[µg/kg]

Uncertainty

[µg/kg]

101 2,565 2,367 2,422 2,5 0,49

102 2,502 1,995 1,923 2,140 0,719

103 3,0 3,1 3,1 3,1 0,6

104 2,65 2,5 2,59 2,58 0,67

105 2,8 2,7 2,6 2,7 0,54

106 2,85 3,12 2,57 2,84 0,48

107 2,16 2,38 2,27 2,27 0,31

108 3,21 3,1 3,3 3,21 0,72

109 2,58 2,57 2,60 2,58 0,45

110 2,67 2,89 2,95 2,83 0,58

111 2,14 2,15 2,25 2,18 0,14

112 3,0 2,9 2,9 2,9 0,6

113 1,19 1,75 1,32 1,42 0,20

114 3,10 3,30 2,90 3,10 0,99

115 3,81 3,95 3,62 3,79 0,38

116 2,52 2,98 2,81 2,76 0,7

117 2,3 2,3 2,3 2,3 0,69

118 2,50 2,48 2,46 2,50 0,28

119 2,79 2,90 3,32 3,01 0,45

120 3,05 2,94 3,06 3,01 0,23

121 2,84 2,83 2,88 2,85 0,43

122 3,05 2,96 3,03 3,03 0,48

123 3,19 3,07 3,16 3,14 0,202

124 n.r. n.r. n.r. 2,84 0,1

515 2,2 1,8 2,2 2,1 0,9

n.r.: not reported

44

Results reported by OCLs for the content of benz[a]anthracene (BAA) in the olive oil test material. Assigned value is 2.79 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

501 3,04 3,1 2,97 3,037 0

502 3,057 2,515 2,771 2,781 0,5562

503 2,60 2,41 2,71 2,57 0,9

504 3,65 3,55 n.r. 3,6 0,54

505 2,65 3,10 3,29 3,01 0,78

506 2,39 2,15 2,10 2,21 0,63

507 2,83 2,97 2,90 2,90 0,60

508 2,45 2,55 2,50 2,5 0,5

509 3,11 3,09 3,04 3,1 0,6

510 1,6 2,4 2,0 2,0 0,8

511 2,43 2,50 2,58 2,5 0,64

512 2,6 2,8 2,8 2,7 0,6

513 1,73 2,48 2,75 2,32 0,28

514 3,05 3,13 3,21 3,13 0,66

516 5,32 5,37 6,06 5,58 0

517 2,47 2,37 2,49 2,44 0,52 518 2,8 2,8 2,9 2,8 0,4

n.r.: not reported

45

Distribution of individual results of replicate determinations reported for the benz[a]anthracene (BAA) content of the olive oil test sample blue triangles: individual results of replicate determinations, blue box: reported expanded measurement uncertainty (k=2), blue horizontal line in blue box: average of replicate determinations, green dotted line: assigned value, red lines: lower and upper limit of satisfactory z-score range

PROLab Plus

Laboratory

113

510

515

102

111

506

107

117

513

517

101

118

508

511

503

104

109

105

512

116

502

518

110

124

106

121

507

112

119

122

505

120

501

103

509

114

514

123

108

504

115

516

cont

ent (

µg/kg)

4

3

2

>5

Sample: Results of replicate analysesMeasurand benz[a]anthraceneNo. of laboratories: 42

Assigned value: 2.790 µg/kg (Reference value)Target s.d.: 0.580 µg/kgRange of tolerance: 1.630 - 3.950 µg/kg (|Z Score| <= 2.00)

Assig

ned value

Limit of tolerance

Limit of tolerance

Kernel density plot of the reported values for proficiency assessment for the benz[a]anthracene (BAA) content of the olive oil test sample

2012 PT 4PAH in oil BAA (OIL_FIN)

µg/kg65.554.543.532.521.51

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Assigned value (Reference value): 2.790 ± 0.020 µg/kg

Mean: 2.733 ± 0.137 µg/kg

Mod

e 1:

1.4

50 µ

g/kg

(2

%)

Mod

e 2:

2.8

70 µ

g/kg

(96

%)

Mod

e 3:

5.5

80 µ

g/kg

(2

%)

46

Results reported by NRLs for the content of benzo[a]pyrene (BAP) in the olive oil test material. Assigned value is 2.27 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

101 2,344 1,945 2,361 2,2 0,44

102 2,116 1,556 1,968 1,88 0,523

103 2,2 2,3 2,3 2,3 0,5

104 2,31 2,18 2,26 2,25 0,77

105 2,1 1,9 2,1 2 0,4

106 2,49 2,18 2,28 2,32 0,35

107 1,78 1,87 1,96 1,87 0,25

108 2,28 2,46 2,52 2,42 0,45

109 2,16 2,13 2,12 2,14 0,43

110 2,25 2,42 2,42 2,36 0,48

111 2,05 2,16 2,09 2,1 0,14

112 2,2 2,2 2,2 2,2 0,5

113 2,11 2,62 2,38 2,37 0,38

114 2,70 2,70 2,80 2,73 0,66

115 2,79 2,85 2,8 2,81 0,28

116 2,12 2,50 2,79 2,47 0,6

117 2,0 2,0 2,0 2,0 0,6

118 2,12 2,11 2,16 2,14 0,35

119 2,31 2,16 2,56 2,34 0,3

120 2,52 2,50 2,60 2,54 0,20

121 2,41 2,41 2,52 2,45 0,24

122 2,47 2,48 2,48 2,48 0,44

123 2,41 2,47 2,36 2,41 0,173

124 n.r. n.r. n.r. 2,17 0,2

515 1,8 1,5 1,7 1,7 0,7

n.r.: not reported

47

Results reported by OCLs for the content of benzo[a]pyrene (BAP) in the olive oil test material. Assigned value is 2.27 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

501 1,78 1,84 1,93 1,85 0

502 1,999 2,101 2,044 2,048 0,4096

503 2,45 2,44 2,72 2,54 0,89

504 2,06 2,18 n.r. 2,12 0,32

505 3,19 3,46 3,05 3,23 0,84

506 1,73 2,07 2,17 1,99 0,6

507 2,26 2,37 2,30 2,31 0,50

508 2,5 2,5 2,55 2,5 0,375

509 2,46 2,44 2,49 2,46 0,49

510 1,5 2,3 2,3 2,0 0,9

511 2,02 2,1 2,2 2,11 0,53

512 2,1 2,2 2,3 2,2 0,7

513 1,32 2,62 1,63 1,87 0,36

514 2,56 2,74 2,34 2,55 0,51

516 2,09 3,99 <10 3,04 0

517 1,95 2,02 2,21 2,06 0,42

518 2,4 2,4 2,4 2,4 0,2

n.r.: not reported

48

Distribution of individual results of replicate determinations reported for the benzo[a]pyrene (BAP) content of the olive oil test sample blue triangles: individual results of replicate determinations, blue box: reported expanded measurement uncertainty (k=2), blue horizontal line in blue box: average of replicate determinations, green dotted line: assigned value, red lines: lower and upper limit of satisfactory z-score range

PROLab Plus

Laboratory

51

550

151

310

710

250

611

710

551

050

251

711

151

150

411

810

912

411

251

210

1

104

103

507

106

119

110

113

518

123

108

121

509

116

122

508

503

120

514

114

115

516

505

cont

ent (

µg/k

g)

4

3

2

Sample: Results of replicate analysesMeasurand benzo[a]pyreneNo. of laboratories: 42


Assig

ned v

alue

Limit of tolerance

Limit of tolerance

Kernel density plot of the reported values for proficiency assessment for the benzo[a]pyrene (BAP) content of the olive oil test sample

2012 PT 4PAH in oil BAP (OIL_FIN)

µg/kg3.53.2532.752.52.2521.751.51.251

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Assigned value (Reference value): 2.270 ± 0.030 µg/kgMean: 2.265 ± 0.094 µg/kg

Mod

e 1:

2.2

90 µ

g/kg

(10

0 %

)

49

Results reported by NRLs for the content of benzo[b]fluoranthene (BBF) in the olive oil test material. Assigned value is 5.32 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

101 4,600 4,592 4,679 4,6 0,92

102 5,185 4,317 4,619 4,707 1,214

103 5,8 6,1 6,0 6,0 1,2

104 5,37 5,05 5,33 5,25 1,57

105 4,5 3,8 5,1 4,5 0,90

106 4,98 4,59 4,50 4,65 0,65

107 4,27 4,44 4,62 4,44 0,50

108 5,57 5,29 5,42 5,43 0,9

109 4,93 4,91 5,01 4,95 1,03

110 5,73 5,85 5,79 5,79 1,17

111 3,45 3,74 3,96 3,72 0,62

112 5,4 5,4 5,3 5,3 1,7

113 2,11 2,80 2,08 2,33 0,35

114 8,80 8,60 8,30 8,57 1,20

115 6,29 6,38 6,31 6,33 0,63

116 7,19 6,65 5,02 6,28 1,6

117 4,7 4,6 4,6 4,7 1,41

118 4,62 4,59 4,63 4,66 0,68

119 5,84 5,18 5,47 5,49 0,88

120 5,44 5,39 5,68 5,50 0,52

121 5,40 5,33 5,58 5,44 0,82

122 5,98 5,90 5,93 5,93 1,02

123 5,34 5,34 5,37 5,35 0,056

124 n.r. n.r. n.r. 5,13 0,4

515 4,4 3,6 4,3 4,1 1,7

n.r.: not reported

50

Results reported by OCLs for the content of benzo[b]fluoranthene (BBF) in the olive oil test material. Assigned value is 5.32 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

501 4,72 5,04 5,14 4,967 0

502 4,360 4,692 4,262 4,438 0,8876

503 8,27 7,78 7,78 7,94 2,78

504 5,20 5,37 n.r. 5,29 0,79

505 5,09 5,33 5,79 5,40 1,43

506 5,87 5,82 5,61 5,77 1,24

507 5,53 5,49 5,4 5,47 1,00

508 5,1 5,3 5,2 5,2 0,78

509 5,8 5,9 5,8 5,8 1,2

510 2,3 3,3 3,0 2,9 1,0

511 6,10 6,50 6,80 6,47 1,64

512 4,6 4,9 5,1 4,8 1,0

513 4,17 6,6 4,05 4,94 0,59

514 5,82 5,74 5,60 5,72 1,2

516 8,65 8,29 8,43 8,45 0

517 5,3 5,1 5,3 5,2 1,0

518 5,4 5,3 5,2 5,3 1,7

n.r.: not reported

51

Distribution of individual results of replicate determinations reported for the benzo[b]fluoranthene (BBF) content of the olive oil test sample blue triangles: individual results of replicate determinations, blue box: reported expanded measurement uncertainty (k=2), blue horizontal line in blue box: average of replicate determinations, green dotted line: assigned value, red lines: lower and upper limit of satisfactory z-score range

PROLab Plus

Laboratory

11

351

011

151

550

210

710

511

810

111

710

610

251

251

310

950

112

450

851

710

4

504

518

123

112

505

108

121

507

119

120

514

506

110

509

122

103

116

115

511

503

516

114

cont

ent (

µg/k

g)

9

8

7

6

5

4

3

2

Sample: Results of replicate analysesMeasurand benzo[b]fluorantheneNo. of laboratories: 42


Assig

ned v

alueLimit of tolerance

Limit of tolerance

Kernel density plot of the reported values for proficiency assessment for the benzo[b]fluoranthene (BBF) content of the olive oil test sample

2012 PT 4PAH in oil BBF (OIL_FIN)

µg/kg98765432

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Mean: 5.258 ± 0.253 µg/kg

Mod

e 1:

2.6

51 µ

g/kg

(4

%)

Mod

e 2:

5.2

69 µ

g/kg

(89

%)

Mod

e 3:

8.3

84 µ

g/kg

(7

%)

52

Results reported by NRLs for the content of chrysene (CHR) in the olive oil test material. Assigned value is 2.77 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

101 2,723 2,555 2,813 2,7 0,54

102 2,065 1,650 2,251 1,989 0,551

103 3,1 3,2 2,9 3,1 0,7

104 2,81 2,59 2,62 2,67 0,59

105 2,7 2,7 3,1 2,8 0,56

106 2,62 2,73 2,93 2,76 0,44

107 2,45 2,19 2,70 2,45 0,72

108 3,01 3,07 3,07 3,05 0,84

109 2,97 3,00 2,98 2,98 0,52

110 2,29 2,45 2,20 2,31 0,49

111 2,72 2,36 2,44 2,51 0,47

112 3,0 3,0 3,1 3,0 0,5

113 2,54 2,83 2,73 2,7 0,45

114 3,3 3,3 3,5 3,37 0,71

115 3,89 3,80 3,79 3,83 0,38

116 2,41 2,51 3,56 2,83 0,7

117 2,4 2,5 2,5 2,5 0,75

118 2,43 2,39 2,43 2,44 0,28

119 2,93 2,65 2,48 2,69 0,38

120 2,81 2,72 2,90 2,81 0,3

121 2,86 2,83 2,90 2,86 0,36

122 3,08 3,02 3,04 3,04 0,5

123 3,40 3,44 3,43 3,42 0,075

124 n.r. n.r. n.r. 3,30 0,2

515 2,2 1,8 2,2 2,1 0,9

n.r.: not reported

53

Results reported by OCLs for the content of chrysene (CHR) in the olive oil test material. Assigned value is 2.77 µg/kg

Lab code

Replicate 1

[µg/kg]

Replicate 2

[µg/kg]

Replicate 3

[µg/kg]


[µg/kg]

Uncertainty

[µg/kg]

501 2,85 2,86 2,91 2,873 0

502 2,412 2,62 2,457 2,496 0,4992

503 4,11 4,19 4,30 4,20 1,47

504 2,87 2,90 n.r. 2,89 0,43

505 2,81 3,16 3,37 3,11 0,81

506 3,69 3,39 3,54 3,54 0,84

507 2,98 3,05 3 3,01 0,6

508 2,6 2,6 2,55 2,6 0,52

509 3,50 3,30 3,20 3,3 0,7

510 1,8 2,7 2,4 2,3 0,9

511 2,26 2,30 2,36 2,31 0,59

512 2,9 2,9 3,0 2,9 0,6

513 2,38 3,01 1,93 2,44 0,46

514 3,16 3,45 3,24 3,26 0,65

516 6,15 8,68 8,70 7,84 0

517 2,25 2,21 2,16 2,21 0,47

518 2,8 2,8 2,9 2,8 0,3

n.r.: not reported

54

Distribution of individual results of replicate determinations of chrysene (CHR) in the olive oil test sample. blue triangles: individual results of replicate determinations, blue box: reported expanded measurement uncertainty (k=2), blue horizontal line in blue box: average of replicate determinations, green dotted line: assigned value, red lines: lower and upper limit of satisfactory z-score range

PROLab Plus

Laboratory

10

2

515

517

510

511

110

118

513

107

117

502

111

508

104

119

101

113

106

120

116

105

518

121

501

504

512

109

507

112

122

108

103

505

514

124

509

114

123

506

115

503

516

cont

ent (

µg/k

g)

5

4

3

2

>6

Sample: Results of replicate analysesMeasurand chryseneNo. of laboratories: 42


Assig

ned v

alue

Limit of tolerance

Limit of tolerance

Kernel density plot of the reported values for proficiency assessment for the chrysene (CHR) content of the olive oil test sample

2012 PT 4PAH in oil CHR (OIL_FIN)

µg/kg87654321

Pro

ba

bili

ty d

en

sit

y

Low

er li

mit

of to

lera

nce

Upp

er li

mit

of to

lera

nce


Mean: 2.838 ± 0.143 µg/kg

Mod

e 1:

2.8

06 µ

g/kg

(98

%)

Mod

e 2:

7.8

39 µ

g/kg

(2

%)

55

Results reported by NRLs for the sum of the four marker PAHs (SUM) in the olive oil test material. Assigned value is 13.2 µg/kg

Lab code


[µg/kg]

Uncertainty

[µg/kg]

101 12,0 1,3

102 10,716 3,007

103 14,5 1,6

104 12,75 1,97

105 12,1 1,2

106 12,57 2,14

107 11,03 0,96

108 14,1 2,83

109 12,65 4,82

110 13,30 1,47

111 10,5 0,8

112 13,5 1,9

113 8,82 0,71

114 17,77 1,83

115 16,76 0,88

116 14,34 3,6

117 11 6,6

118 11,73 2,06

119 13,53 3,94

120 13,86 0,67

121 13,60 1,02

122 14,48 1,31

123 14,33 0,282

124 13,4 1,3

515 10 4,2

n.r.: not reported

56

Results reported by OCLs for the sum of the four marker PAHs (SUM) in the olive oil test material. Assigned value is 13.2 µg/kg

Lab code


[µg/kg]

Uncertainty

[µg/kg]

501 12,727 0

502 11,763 2,3526

503 17,25 3,39

504 13,89 2,08

505 14,72 2,00

506 13,62 1,73

507 13,69 3

508 12,8 2,56

509 14,7 2,9

510 9,2 3,6

511 13,39 1,93

512 12,7 1,5

513 11,57 2,2

514 14,66 1,6

516 24,91 0

517 11,9 2,5

518 13,3 n.r.

n.r.: not reported

57

Distribution of individual results of replicate determinations of the SUM of the content of the 4 PAH in the olive oil test sample. blue triangles: individual results of replicate determinations, blue box: reported expanded measurement uncertainty (k=2), blue horizontal line in blue box: average of replicate determinations, green dotted line: assigned value, red lines: lower and upper limit of satisfactory z-score range

PROLab Plus

Laboratory

11

351

051

5

111

102

117

107

513

118

502

517

101

105

106

109

512

501

104

508

110

518

511

124

112

119

121

506

507

120

504

108

123

116

122

103

514

509

505

115

503

114

516

cont

ent (

µg/k

g)

20.0

17.5

15.0

12.5

10.0

7.5

5.0

>24

Sample: Value for proficiency assessmentMeasurand Sum of 4 PAHsNo. of laboratories: 42


Assig

ned v

alue

Limit of tolerance

Limit of tolerance

Kernel density plot of the reported values for proficiency assessment for the SUM of 4 PAH content of the olive oil test sample

2012 PT 4PAH in oil SUM (OIL_FIN)

µg/kg26242220181614121086

Pro

ba

bili

ty d

en

sit

y

Low

er li

mit

of to

lera

nce

Upp

er li

mit

of to

lera

nce


Mean: 13.091 ± 0.571 µg/kg

Mod

e 1:

13.

440

µg/

kg (

92 %

)

Mod

e 2:

17.

140

µg/k

g (6

%)

Mod

e 3:

24.

900

µg/k

g (2

%)

58

ANNEX 9: Laboratory means and repeatability standard deviation

Lab means and repeatability standard deviation for the determination of BAA in the olive oil test material

NRLs

Chart of repeatability standard deviations

PROLab Plus

Laboratory mean [µg/kg]43.93.83.73.63.53.43.33.23.132.92.82.72.62.52.42.32.22.121.91.81.71.61.51.4

Rep

eata

bility

stan

dard

dev

iatio

n

0.32

0.3

0.28

0.26

0.24

0.22

0.2

0.18

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

0

113

515

102

111

107

117

101

118

104

109

105

116

110

106

121

112

119

122

120103

114

123

108

115

OCLs


PROLab Plus

Laboratory mean [µg/kg]5.65.45.254.84.64.44.243.83.63.43.232.82.62.42.221.81.6

Rep

eata

bility

stan

dard

dev

iatio

n

0.5

0.45

0.4

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

510

506

513

517508

511

503

512

502

518

507

505

501

509

514 504

516

59

Lab means and repeatability standard deviation for the determination of BAP in the olive oil test material

NRLs


PROLab Plus

Laboratory mean [µg/kg]3.33.23.132.92.82.72.62.52.42.32.22.121.91.81.71.61.51.41.3

Rep

eata

bility

stan

dard

dev

iatio

n

0.34

0.32

0.3

0.28

0.26

0.24

0.22

0.2

0.18

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

0

515

107

102

117

105

111

118109

112

101

104103

106

119

110

113

123

108

121

122

120 114

115

OCLs


PROLab Plus

Laboratory mean [µg/kg]3.33.23.132.92.82.72.62.52.42.32.22.121.91.81.71.61.51.41.3

Rep

eata

bility

stan

dard

dev

iatio

n

1.3

1.2

1.1

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

501

513

506

510

502

517511

504

512507

518509508

503 514

516

505

60

Lab means and repeatability standard deviation for the determination of BBF in the olive oil test material

NRLs


PROLab Plus

Laboratory mean [µg/kg]8.587.576.565.554.543.532.5

Rep

eata

bility

stan

dard

dev

iatio

n

1.1

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

113

111

515

107

105

118 101

117

106

102

109

104

123 112108

121

119

120110122

103

116

115

114

OCLs


PROLab Plus

Laboratory mean [µg/kg]8.587.576.565.554.543.53

Rep

eata

bility

stan

dard

dev

iatio

n

1.4

1.3

1.2

1.1

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

510

502 512

513

501

508

517504

518

505

507514

506

509

511 503

516

61

Lab means and repeatability standard deviation for the determination of CHR in the olive oil test material

NRLs


PROLab Plus

Laboratory mean [µg/kg]43.93.83.73.63.53.43.33.23.132.92.82.72.62.52.42.32.22.121.91.81.71.61.5

Rep

eata

bility

stan

dard

dev

iatio

n

0.6

0.55

0.5

0.45

0.4

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

102

515

110

118

107

117

111

104

119

101113

106

120

116

105

121109

112

122108

103

114

123

115

OCLs


PROLab Plus

Laboratory mean [µg/kg]4.44.243.83.63.43.232.82.62.42.221.81.6

Rep

eata

bility

stan

dard

dev

iatio

n

0.55

0.5

0.45

0.4

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

517

510

511

513

502

508

518501504

512507

505

514509 506

503

Participant 516 is outside of

the displayed range

European Commission

EUR 25999 EN – Joint Research Centre – Institute for Reference Materials and Measurements

Title: Report on the 11th inter-laboratory comparison organised by the European Union Reference Laboratory for Polycyclic

Aromatic Hydrocarbons - Four marker PAHs in spiked olive oil

Authors: Stefanka Bratinova, Philippe Verlinde and Thomas Wenzl

Luxembourg: Publications Office of the European Union

2013 – 64 pp. – 21.0 x 29.7 cm

EUR – Scientific and Technical Research series – ISSN 1831-9424 (online)

ISBN 978-92-79-30497-2

doi:10.2787/61833

Abstract

The proficiency test here reported concerned the determination of the four marker polycyclic aromatic hydrocarbons (PAHs) in an

olive oil test sample: benz[a]anthacene, benzo[a]pyrene, benzo[b]fluoranthene, and chrysene. Participants to these PT were

National Reference Laboratories for PAHs (NRLs-PAHs) and EU official food control laboratories. The number of participants was

43. The PT was organised according to ISO Standard 17043:2010.

The test material used was olive oil spiked with the target PAHs. Participants also received a solution of the PAHs either in an

organic solvent for checking their instrument calibration.

The results from participants were rated with z-scores and zeta-scores. About 94.4 % and 90.5 % of the results reported by

NRLs and OCLs respectively were attributed with z-scores with an absolute value of below two, which is the threshold for

satisfactory performance. The zeta-score ratings were worse, which indicates problems in the estimation of reliable

measurement uncertainty values.

As the Commission’s in-house science service, the Joint Research Centre’s mission is to provide EU

policies with independent, evidence-based scientific and technical support throughout the whole policy

cycle.

Working in close cooperation with policy Directorates-General, the JRC addresses key societal

challenges while stimulating innovation through developing new standards, methods and tools, and

sharing and transferring its know-how to the Member States and international community.

Key policy areas include: environment and climate change; energy and transport; agriculture and food

security; health and consumer protection; information society and digital agenda; safety and security

including nuclear; all supported through a cross-cutting and multi-disciplinary approach.

LA

-NA

-25

99

9-E

N-N